CN115216847A - Method and device for preparing metal material by multi-magnetic field assisted directional solidification - Google Patents

Abstract

The invention discloses a method and a device for preparing a metal material by multi-magnetic-field-assisted directional solidification, which comprises a smelting device, a magnetic field generating device, a vacuum cavity, a cooling tank, a temperature measuring system, a drawing device, a vacuum system and an experimental atmosphere source; the cooling tank is arranged at the bottom of the vacuum cavity, the smelting device is arranged in the vacuum cavity, the magnetic field generating device is arranged in the cooling tank, the vacuumizing system is connected with the inner cavity of the vacuum cavity and is used for vacuumizing the vacuum cavity, and the experimental atmosphere source is connected with the inner cavity of the vacuum cavity and is used for filling experimental atmosphere into the vacuumized vacuum cavity; the temperature measuring system is used for monitoring the temperature of the upper surface of the sample in the vacuum cavity; according to the invention, the directional solidification drawing speed, the magnetic field intensity and the magnetic field type are regulated and controlled in the directional solidification process of the metal melt, and the material structure can be designed according to the requirements of different sections of the material on performance differentiation in a complex application environment. The prepared material has gradient structure and performance along the radial direction.

Description

Method and device for preparing metal material by multi-magnetic field assisted directional solidification

technical field

The invention relates to the technical field of metal material preparation, in particular to a method and a device for preparing metal materials by multi-magnetic field-assisted directional solidification.

Background technique

During the solidification process, a magnetic field is applied to the metal melt, and by changing the convection inside the melt to control its mass transfer and heat transfer behavior, the structure and properties of the metal material can be effectively improved. At present, the main types of applied magnetic fields include steady-state magnetic fields and traveling-wave magnetic fields. The convection behavior in the melt under different magnetic fields shows great differences. Under the action of the transverse steady magnetic field, the solute will show segregation behavior towards the crucible wall, which is widely used in the field of metal impurity removal; the longitudinal steady magnetic field can effectively control the crystal orientation characteristics of the alloy material; the traveling wave magnetic field can promote the convection inside the melt, so that the Reduce shrinkage, segregation and other defects.

In the directional solidification technique, the alloy melt grows against the temperature gradient, and the crystal solidifies in the opposite direction to the heat flow. This technique can obtain columnar or single crystal structures with the same orientation, thereby improving the application properties of the material. Compared with traditional solidification methods, directional solidification technology has broader application prospects in the field of high-performance alloy preparation. However, due to the limitations of technical conditions such as directional solidification drawing speed, it has certain limitations in the development and manufacture of new functional metal materials. The directional solidification technology with external magnetic field proposed in recent years combines the advantages of magnetic field regulation and directional solidification. Chinese patent CN108655375A proposes a method for preparing gradient materials by directional solidification under the condition of axially stable magnetic field, by changing the magnetic induction intensity of the external magnetic field to prepare functionally graded materials with gradient properties; Chinese patent CN104625022A proposes a method for preparing gradient materials by directional solidification A method for removing impurities from metal materials by applying a transverse magnetic field. The thermal electromagnetic flow formed in the metal melt is used to make the inclusions segregate to one side of the crucible; Chinese patent CN102071469B proposes a device for applying a traveling wave magnetic field during the directional solidification process, which can change the strength and frequency of the traveling wave magnetic field by changing the intensity and frequency of the traveling wave magnetic field Refine the dendritic structure of the material. The above prior art mainly uses a single magnetic field to control the microstructure and properties of metal materials, and the solidification mechanism of metal materials and the design of preparation devices under multi-magnetic field conditions have not been involved. In the design of the directional solidification device with the applied magnetic field, the volume of the magnetic field generator is large and the types of the applied magnetic field are few. At the same time, in the preparation of new metal materials, the gradient difference along the directional growth direction of the materials prepared by the control of a single external magnetic field is small, and it is difficult to meet the differentiated requirements of the performance of each section of the material in the complex application environment.

In conclusion, it is an urgent problem for those skilled in the art to provide a method and device for preparing metal materials by multi-magnetic field-assisted directional solidification.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method and device for preparing metal materials by multi-magnetic field-assisted directional solidification, so as to solve the problems existing in the above-mentioned prior art. The material structure is designed according to the requirements of different performances of different sections of the material in the complex application environment, which provides a way for the design and development of new metal materials.

For achieving the above object, the present invention provides the following scheme:

The invention provides a method for preparing metal materials by multi-magnetic field-assisted directional solidification, comprising the following steps:

(1) Select high-purity bulk metal raw materials, and configure the required metal materials in proportion; process the material into a suitable size and load it into a ceramic crucible and connect the crucible with the pulling rod;

(2) Four kinds of magnetic field generators are installed in the cooling tank to correspond to the mobile device; the working position of the magnetic field generator can be adjusted through the magnetic field lifting assembly and the magnetic field translation assembly;

(3) Evacuate the vacuum chamber; melt the alloy material into a metal melt, so as to realize the directional growth of the alloy in the directional pulling process of the pulling rod;

(4) The first solidification stage: start the pulling device to pull the metal melt into the Ga-In-Sn liquid metal cooling medium of the cooling tank for directional solidification; the metal melt solidifies under the action of the first external magnetic field, and the magnetic field Mainly acts on the solid-liquid interface of the material; the first externally applied magnetic field can be a transverse steady magnetic field, a longitudinal steady magnetic field, a transverse traveling wave magnetic field, a longitudinal traveling wave magnetic field or a composite magnetic field formed by any two of the four magnetic fields;

(5) The second solidification stage: when the material is immersed in the Ga-In-Sn liquid metal cooling medium at a set distance, the position of the magnetic field generator is adjusted so that the material solidifies under the action of the second external magnetic field; the second external magnetic field has the same characteristics as the first external magnetic field. Different types, strengths or frequencies of magnetic fields;

(6) nth solidification stage; when the material is immersed in the Ga-In-Sn liquid metal cooling medium for a set distance, adjust the position of the magnetic field generator so that the material solidifies under the action of the nth external magnetic field;

(7) After the metal material is cooled to room temperature, it is taken out, and the metal material has multiple solidified structures with different directional growth characteristics along the radial direction.

The invention also provides a device for preparing metal materials by multi-magnetic field-assisted directional solidification, which is applied to the above-mentioned method for preparing metal materials by multi-magnetic field-assisted directional solidification, including a smelting device, a magnetic field generating device, a vacuum cavity, a cooling tank, a measuring Warming system, pulling device, vacuuming system and experimental atmosphere source;

The cooling tank is arranged at the bottom of the vacuum chamber, the smelting device is arranged in the vacuum chamber, the magnetic field generating device is arranged in the cooling tank, and the vacuum pumping system is connected to the vacuum chamber The inner cavity of the vacuum chamber is used for evacuating the vacuum chamber, and the experimental atmosphere source is connected to the inner cavity of the vacuum chamber, and is used to fill the experimental atmosphere into the vacuum chamber after being evacuated; The temperature system is used to monitor the temperature of the upper surface of the sample in the vacuum chamber;

The smelting device includes an induction coil, a graphite sleeve and a crucible; the graphite sleeve is cylindrical graphite, the induction coil is wound on the outside of the graphite sleeve, the crucible is arranged in the graphite sleeve, and the crucible The bottom is connected with the pulling device, and the pulling device controls the crucible to move vertically in the graphite sleeve; the bottom of the graphite sleeve is provided with an annular graphite pad, and the bottom of the graphite pad is provided with a ceramic a pad, a graphite felt is arranged between the ceramic pad and the top plate of the cooling tank at the bottom;

The magnetic field generating device includes a magnetic field generator, a thermal protective cover, a magnetic field control device and a power supply device; the magnetic field generator includes a longitudinal steady magnetic field generator, a transverse steady magnetic field generator, a longitudinal traveling wave magnetic field generator and a transverse traveling wave magnetic field generator. wave magnetic field generator;

The longitudinal stable magnetic field generator is composed of a ring-shaped permanent magnet and a thermal protective sleeve sleeved on the outside of the ring-shaped permanent magnet, and can generate a stable and constant magnetic field parallel to the direction of directional solidification;

The lateral stable magnetic field generator includes two square permanent magnets placed opposite to each other and a thermal protective sleeve sleeved on the outside of the square permanent magnets. Provide a transverse stable magnetic field;

The longitudinal traveling wave magnetic field generator is composed of a longitudinally distributed copper coil and a thermal protective sleeve sleeved on the outside of the copper coil, and can generate a traveling wave magnetic field parallel to the direction of directional solidification;

The transverse traveling wave magnetic field generator includes two rectangular coils placed opposite to each other and a thermal protective sleeve sleeved on the outside of the rectangular coils, which can generate a transverse traveling wave magnetic field;

The magnetic field control device includes a magnetic field lifting component and a magnetic field translation component, wherein the magnetic field lifting component is composed of a lifting rod and a servo motor, and is used to control the lifting and lowering of the annular permanent magnet and the copper coil in the cooling tank cavity; The magnetic field translation assembly includes a translation support rod and a second servo motor, which are used to control the horizontal position of the square permanent magnet and the rectangular coil;

The power supply device is used for supplying power to the internal coil of the magnetic field generating device.

Preferably, the vacuum pumping system includes a mechanical pump and a molecular pump, the mechanical pump is connected to the molecular pump, and the molecular pump pipeline is connected to the cavity of the vacuum chamber.

Preferably, the induction coil is a red copper coil in which circulating cooling water is circulated.

Preferably, the pulling device includes a pulling motor and a pulling rod, the bottom of the pulling rod is connected to the pulling motor, the top of the pulling rod is connected to the crucible through a molybdenum alloy adapter, and the crucible has a flat bottom cylindrical corundum crucible.

Preferably, the thermal protective sheath is an alumina ceramic sheath.

Preferably, the cooling tank includes a cylindrical demagnetized stainless steel tank, a Ga-In-Sn liquid metal cooling medium and a copper tube through which circulating cooling water flows, and the Ga-In-Sn liquid metal cooling medium is installed in the In the tank, the copper tube is located in the Ga-In-Sn liquid metal cooling medium in the tank.

Preferably, the power supply device includes an electrode flange and a power supply; the electrode flange is mounted on the side wall of the vacuum chamber, and the electrode flange connects the external power supply and the internal longitudinal Traveling wave magnetic field generator and transverse traveling wave magnetic field generator.

Preferably, the side walls of the vacuum chamber and the cooling tank are double-layer water-cooling structures with a water-cooling interlayer inside, and the water-cooling interlayers of the vacuum chamber and the cooling tank are connected to the water cooler through pipes.

Preferably, the temperature measuring device is an infrared thermometer; the infrared thermometer is installed on the top of the vacuum cavity.

The present invention has achieved the following beneficial technical effects with respect to the prior art:

1. The metal material preparation method provided by the present invention regulates the directional solidification drawing speed, the magnetic field strength and the magnetic field generator type in the directional solidification process of the metal melt, and can design the material structure according to the requirements of the complex application environment for different performances of different sections of the material . The prepared material has gradient structure and properties along the radial direction.

2. The magnetic field generating equipment of the directional solidification device provided by the present invention can be switched directly in the cavity, which can meet the directional solidification of metal materials in a single magnetic field and a composite magnetic field, simplify the experimental operation process and greatly reduce the cost of experimental equipment.

3. The magnetic field generating device of the present invention adopts liquid metal cooling and multi-layer heat insulation treatment of graphite pad, ceramic pad and graphite felt, so as to realize the stable operation of the magnetic field generator in the high temperature and high frequency magnetic field environment.

4. The distance between all the magnetic field generating devices of the present invention and the sample is very small, which effectively reduces the attenuation of the magnetic field with the distance, and reduces the energy consumption and experiment cost. It is a more low-carbon and environmentally friendly method for preparing new high-temperature metal materials.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

1 is a schematic diagram of a method for preparing a metal material by multi-magnetic field-assisted directional solidification in the present invention;

2 is a schematic structural diagram of a device for preparing metal materials by multi-magnetic field-assisted directional solidification according to the present invention;

Fig. 3 is the horizontal schematic diagram of the magnetic field generating device in Fig. 2;

Fig. 4 is the vertical schematic diagram of the magnetic field generating device in Fig. 2;

5 is a schematic structural diagram of a longitudinal steady magnetic field generator;

Fig. 6 is the structural representation of the transverse steady magnetic field generator;

7 is a schematic structural diagram of a longitudinal traveling wave magnetic field generator;

8 is a schematic structural diagram of a transverse traveling wave magnetic field generator;

In the figure: 1-induction coil; 2-graphite sleeve; 3-crucible; 4-ceramic pad; 5-magnetic field generator; 6-mechanical pump; 7-molecular pump; 8-experimental atmosphere source; 9-vacuum chamber; 10-water cooler; 11-infrared thermometer; 12-pulling device; 13-ring permanent magnet; 14-square permanent magnet; 15-copper coil; 16-rectangular coil; 17-servo motor two; 18-translation support Rod; 19-Ga-In-Sn liquid metal cooling medium; 20-drawing rod; 21-servo motor one; 22-lifting rod; 23-cooling tank; 24-sample; 25-thermal protection jacket.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The purpose of the present invention is to provide a device and method for preparing metal materials by multi-magnetic field-assisted directional solidification, so as to solve the problems existing in the prior art.

In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

This embodiment provides a method for preparing a metal material by multi-magnetic field-assisted directional solidification, as shown in FIG. 1 , including the following steps:

(1) select high-purity bulk metal raw materials, and configure the required metal materials in proportion; the material is processed into a suitable size and loaded into the ceramic crucible 3 and the crucible 3 is connected with the pulling rod 20;

(2) four kinds of magnetic field generators 5 are installed in the cooling tank 23 to correspond to the mobile device; the working position of the magnetic field generator 5 can be adjusted by the magnetic field lifting assembly and the magnetic field translation assembly;

(3) evacuating the vacuum chamber 9; melting the alloy material into a metal melt, so as to realize the directional growth of the alloy in the directional pulling process of the pulling rod 20;

(4) The first solidification stage: start the pulling device 12 to pull the metal melt into the Ga-In-Sn liquid metal cooling medium 19 of the cooling tank 23 for directional solidification; the metal melt solidifies under the action of the first external magnetic field, The magnetic field mainly acts on the solid-liquid interface of the material; the first external magnetic field can be a transverse steady magnetic field, a longitudinal steady magnetic field, a transverse traveling wave magnetic field, a longitudinal traveling wave magnetic field or a composite magnetic field formed by any two of the four magnetic fields;

(5) The second solidification stage: when the material is immersed in the Ga-In-Sn liquid metal cooling medium at a distance of 19× ₁ , the position of the magnetic field generator 5 is adjusted so that the material is solidified under the action of the second external magnetic field; different types, intensities or frequencies;

(6) the nth solidification stage; when the material is immersed in the Ga-In-Sn liquid metal cooling medium x _n-1 distance, adjust the position of the magnetic field generator 5 so that the material solidifies under the action of the nth external magnetic field;

(7) After the metal material is cooled to room temperature, it is taken out, and the metal material has multiple solidified structures with different directional growth characteristics along the radial direction.

This embodiment also provides a device for preparing metal materials by multi-magnetic field-assisted directional solidification, which is applied to the above-mentioned method for preparing metal materials by multi-magnetic field-assisted directional solidification, as shown in Figures 2-8, including a smelting device and a magnetic field generating device , a vacuum chamber 9, a cooling tank 23, a temperature measurement system, a pulling device 12, a vacuum pumping system and an experimental atmosphere source 8;

The cooling tank 23 is arranged at the bottom of the vacuum chamber 9, the smelting device is arranged in the vacuum chamber 9, the magnetic field generating device is arranged in the cooling tank 23, and the vacuum pumping system is connected to the inner cavity of the vacuum chamber 9, and is used for the vacuum chamber. 9. Evacuate, and the experimental atmosphere source 8 is connected to the inner cavity of the vacuum chamber 9 for filling the experimental atmosphere into the evacuated vacuum chamber 9; the temperature measurement system is used to monitor the upper surface of the sample 24 in the vacuum chamber 9 temperature;

The smelting device includes an induction coil 1, a graphite sleeve 2 and a crucible 3; the graphite sleeve 2 is cylindrical graphite, the induction coil 1 is a copper coil 15 with circulating cooling water inside, the induction coil 1 is wound on the outside of the graphite sleeve 2, and the crucible 3 It is arranged in the graphite sleeve 2, the bottom of the crucible 3 is connected with the pulling device 12, and the pulling device 12 controls the crucible 3 to move vertically in the graphite sleeve 2; the bottom of the graphite sleeve 2 is provided with an annular graphite pad, and the bottom of the graphite pad is provided with There is a ceramic pad to reduce the thermal radiation of the magnetic field generating device, and a graphite felt is arranged between the ceramic pad and the top plate of the cooling tank 23 at the bottom to reduce the temperature gradient inside the ceramic pad and prevent the ceramic pad from breaking;

The magnetic field generating device includes a magnetic field generator 5, a thermal protective sheath 25, a magnetic field control device and a power supply device; the magnetic field generator 5 includes a longitudinal steady magnetic field generator, a transverse steady magnetic field generator, a longitudinal traveling wave magnetic field generator and a transverse traveling wave magnetic field generator;

The longitudinal stable magnetic field generator is composed of a ring-shaped permanent magnet 13 and a thermal protective sleeve 25 sleeved on the outside of the ring-shaped permanent magnet 13, and can generate a stable and constant magnetic field parallel to the direction of directional solidification;

The lateral stable magnetic field generator includes two square permanent magnets 14 placed opposite to each other and a thermal protection sleeve 25 sleeved on the outside of the square permanent magnet 14. The N poles of the two square permanent magnets 14 are placed opposite to the S poles, which can provide a lateral stable magnetic field;

The longitudinal traveling wave magnetic field generator is composed of a longitudinally distributed copper coil 15 and a thermal protective sheath 25 sleeved on the outside of the copper coil 15, and can generate a traveling wave magnetic field parallel to the direction of directional solidification;

The transverse traveling wave magnetic field generator includes two rectangular coils 16 placed opposite to each other and a heat shield 25 sleeved on the outside of the rectangular coil 16, which can generate a transverse traveling wave magnetic field;

Specifically, the annular permanent magnet 13 and the copper coil 15 are arranged on the top of the cooling tank 23, and the two are arranged concentrically, and the annular permanent magnet 13 is located on the outer periphery of the copper coil 15; the two square permanent magnets 14 and the two rectangular coils 16 are respectively arranged On both sides of the top of the cooling tank 23 , the pulling rods 20 pass through the center of the copper coil 15 and pass between the square permanent magnet 14 and the rectangular coil 16 . The magnetic field generator can provide 0-5T transverse stable magnetic field, 0-5T longitudinal stable magnetic field, 0-200mT longitudinal traveling wave magnetic field and 0-200mT transverse traveling wave magnetic field, and the traveling wave magnetic field frequency is 10-500Hz.

The magnetic field control device includes a magnetic field lifting component and a magnetic field translation component, wherein the magnetic field lifting component is composed of a lifting rod 22 and a servo motor 1 21, which is used to control the lifting and lowering of the annular permanent magnet 13 and the copper coil 15 in the cavity of the cooling tank 23; the lifting rod 22 The bottom end is connected to the servo motor one 21, and the top end is connected to the annular permanent magnet 13 and the copper coil 15 through the lifting platform at the same time.

The magnetic field translation assembly includes a translation support rod 18 and a second servo motor 17, which are used to control the horizontal position of the square permanent magnet 14 and the rectangular coil 16; the second servo motor 17 is provided with two, and the two servo motors 2 17 are respectively connected to a translation support rod 18. The translation support rod 18 is connected to the push plate, and the two push plates are respectively installed on the two square permanent magnets 14 and the two rectangular coils 16. The two servo motors 17 can respectively control the lateral positions of the square permanent magnet 14 and the rectangular coil 16 .

The power supply device is used to supply power to the internal coil of the magnetic field generating device; the power supply device includes an electrode flange and a power supply, the electrode flange is installed on the side wall of the vacuum chamber 9, and the electrode flange connects the external power supply and the internal power supply through wires. Longitudinal traveling wave magnetic field generator and transverse traveling wave magnetic field generator.

In this specific embodiment, the vacuum pumping system includes a mechanical pump 6 and a molecular pump 7 , the mechanical pump 6 is connected to the molecular pump 7 , and the molecular pump 7 is connected to the cavity of the vacuum chamber 9 via a pipeline. The vacuum pumping system can pump the cavity to 1×10 ^-4 -1×10 ^-6 Pa; the experimental atmosphere source 8 is argon. After the vacuum pumping system has pumped the cavity to a vacuum, the solenoid valve can be opened to the vacuum cavity 9 The chamber is backfilled with argon.

In this specific embodiment, the pulling device 12 includes a pulling motor and a pulling rod 20, the bottom of the pulling rod 20 is connected to the pulling motor, and the pulling rod 20 can realize a pulling speed of 1-500 μm/s under the driving of the pulling motor. . The top of the pulling rod 20 is connected to the crucible 3 through a molybdenum alloy adapter, and the crucible 3 is a cylindrical corundum crucible 3 with a flat bottom.

In this specific embodiment, the thermal protection cover 25 is an alumina ceramic cover, which is used to prevent the internal magnetic field generator 5 from being damaged by high temperature.

In this specific embodiment, the cooling tank 23 includes a cylindrical demagnetized stainless steel tank body, a Ga-In-Sn liquid metal cooling medium 19 and a copper tube through which circulating cooling water flows, and a Ga-In-Sn liquid metal cooling medium 19. Installed in the tank, the copper tube is located in the Ga-In-Sn liquid metal cooling medium 19 in the tank.

In this specific embodiment, the side walls of the vacuum chamber 9 and the cooling tank 23 are double-layer water-cooled structures with a water-cooled interlayer inside, and the water-cooled interlayers of the vacuum chamber 9 and the cooling tank 23 are connected to the water cooler 10 through pipes.

In this specific embodiment, the temperature measuring device is an infrared thermometer 11 , the infrared thermometer 11 is installed on the top of the vacuum chamber 9 , and the temperature measurement range of the infrared thermometer 11 is 500-2500° C. It can monitor the temperature of the sample 24 in real time. surface temperature.

Example 1:

This embodiment provides an experimental scheme for the directional solidification of metal materials under the action of a multi-level magnetic field.

(1) Select high-purity Ni with a purity of 99.995% and high-purity Cu to configure a Ni-30Cu (wt.%) alloy, and smelt in a high-vacuum suction casting furnace. Great.

(2) The annular permanent magnet 13 with an outer diameter of 60mm and an inner diameter of 36mm and a thickness of 60mm provides the first-level magnetic field, the 200-turn copper coil 15 with an inner diameter of 14mm provides the second-level magnetic field, and the 50×50×50mm square permanent magnet 14 provides the third-level magnetic field. A 50x50mm 200-turn rectangular coil 16 provides the fourth magnetic field. The magnetic field generators 5 are all installed in the heat shield 25 . The annular permanent magnet 13 and the longitudinally distributed copper coil 15 are placed coaxially with the sample 24 ; the square permanent magnet 14 and the rectangular coil 16 are arranged opposite to the N and S poles. Start the servo motor to make the first-level magnetic field act on the solid-liquid interface of the metal melt.

Put the alloy rod into the crucible 3 with an inner diameter of 10 mm and an outer diameter of 12 mm, use alumina powder and silica sol to configure an adhesive to bond the crucible 3 to the upper end of the pulling rod 20, and place a graphite sleeve 2 with an outer diameter of 40 mm and an inner diameter of 20 mm and a height of 200 mm.

(4) Use a vacuuming system to evacuate to 5×10 ^-6 Pa, and then backflush high-purity argon into the chamber to 0.5×10 ⁵ Pa.

(5) Turn on the high-frequency power supply for heating and the infrared thermometer 11, and the infrared thermometer 11 shows that the experiment starts when the alloy temperature rises to an overheated temperature of 200K.

(6) The first solidification stage: start the power supply of the pulling device 12, and the sample 24 is immersed in the liquid metal at a rate of 5 μm/s; the second solidification stage: after the sample 24 is immersed in the liquid metal for 5 mm, adjust the second-level magnetic field to act on the solid-liquid interface of the material The third solidification stage: after the sample 24 is immersed in liquid metal for 10mm, adjust the third-level magnetic field to act on the material solid-liquid interface; the fourth solidification stage: after the sample 24 is immersed in the liquid metal for 15mm, adjust the fourth-level magnetic field to act on the material solid-liquid interface.

(7) After the sample 24 is immersed in the liquid metal for 20 mm, turn off the power supply of the pulling device 12, the coil power supply and the high-frequency heating power supply. After the sample 24 is cooled to room temperature, the cavity is opened, and the sample 24 and the crucible 3 are taken out together. The metal material prepared under the condition of the fourth-level magnetic field is obtained after demoulding.

Example 2:

This embodiment provides an experimental scheme for the directional solidification of metal materials by applying a multi-stage composite magnetic field.

(1) Select high-purity Ni with a purity of 99.995% and 99.95% high-purity Al to configure a Ni-25Al (wt.%) alloy, and smelt in a high-vacuum suction casting furnace. Al alloy rod.

(2) The ring-shaped permanent magnet 13 with an outer diameter of 60mm and an inner diameter of 36mm and a thickness of 60mm and a copper coil 15 with an outer diameter of 34mm and an inner diameter of 14mm and 200 turns provide the first-level magnetic field at the same time. Provides a second-level magnetic field. The annular permanent magnet 13 is placed coaxially with the longitudinally distributed copper coil 15 and the sample 24; the rectangular coil 16 is placed opposite to the S pole with a distance of 16 mm, and the square permanent magnet 14 is placed opposite to the S pole with a distance of 58 mm. Adjust the first-level magnetic field to the solid-liquid interface of the metal material.

(3) Put the alloy rod into the crucible 3 with an inner diameter of 10 mm and an outer diameter of 12 mm, use alumina powder and silica sol to configure an adhesive to bond the crucible 3 and the upper end of the pulling rod 20, and place a graphite sleeve with an outer diameter of 40 mm and an inner diameter of 20 mm and a height of 200 mm. 2.

(4) Use a vacuum pump to evacuate to 1×10 ^-5 Pa, and then backflush high-purity argon into the chamber to 0.5×10 ⁵ Pa.

(5) Turn on the high-frequency power supply heating and the infrared thermometer 11, and the infrared data shows that the experiment starts when the alloy temperature rises to overheating 300K.

(6) The first solidification stage: start the power supply of the pulling device 12 and the coil power supply, and the sample 24 is immersed in the liquid metal at a rate of 50 μm/s; the second solidification stage: after the sample 24 is immersed in the liquid metal for 15 mm, adjust the first-level magnetic field to be far away from Sample 24; start the servo motor two 17 so that the second-level magnetic field acts on the solid-liquid interface of the sample 24.

(7) After the sample 24 is immersed in the liquid metal for 20 mm, turn off the power supply of the pulling device 12, the coil power supply and the high-frequency heating power supply. After the sample 24 is cooled to room temperature, the cavity is opened, and the sample 24 and the crucible 3 are taken out together. The metal materials prepared under the two magnetic field coupling conditions were obtained after demolding.

Example 3

This embodiment provides a directional solidification of a metal material under the action of a single magnetic field

(1) Select high-purity Ti, high-purity Al and high-purity V alloys with a purity of 99.95% to configure a Ti-6Al-4V (wt.%) alloy, and smelt in a high-vacuum suction casting furnace. Casting to obtain Ti-6Al-4V alloy rods.

(2) Select the annular permanent magnet 13 with an outer diameter of 80 mm and an inner diameter of 15 mm and a thickness of 60 mm to provide a longitudinal stable magnetic field.

(3) Put the alloy rod into the crucible 3 with an inner diameter of 10 mm and an outer diameter of 12 mm, use alumina powder and silica sol to configure an adhesive to bond the crucible 3 and the upper end of the pulling rod 20, and place a graphite sleeve with an outer diameter of 40 mm and an inner diameter of 20 mm and a height of 200 mm. 2.

(4) Use a vacuum pump to evacuate to 1×10 ^-5 Pa, and then backflush high-purity argon into the chamber to 0.5×10 ⁵ Pa.

(5) Turn on the high-frequency power heating and the infrared detection probe. When the infrared data showed that the alloy temperature rose to an overheat of 100K, the power supply of the pulling device 12 was activated, and the sample 24 was immersed in the liquid metal at a rate of 200 μm/s.

(6) After the sample 24 is immersed in the liquid metal for 50 mm, turn off the drawing power and the high-frequency heating power. After the sample 24 is cooled to room temperature, the cavity is opened, and the sample 24 and the crucible 3 are taken out together. After demoulding, a directional solidification metal material is obtained by applying a longitudinally stable magnetic field.

The present invention uses specific examples to illustrate the principles and implementations of the present invention, and the descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention; There will be changes in the specific implementation and application scope. In conclusion, the contents of this specification should not be construed as limiting the present invention.

Claims (10)

1. a method for preparing metal material by multi-magnetic field assisted directional solidification, is characterized in that, comprises the following steps: (1) Select high-purity bulk metal raw materials, and configure the required metal materials in proportion; process the material into a suitable size and load it into a ceramic crucible and connect the crucible with the pulling rod; (2) Four kinds of magnetic field generators are installed in the cooling tank to correspond to the mobile device; the working position of the magnetic field generator can be adjusted through the magnetic field lifting assembly and the magnetic field translation assembly; (3) Evacuate the vacuum chamber; melt the alloy material into a metal melt, so as to realize the directional growth of the alloy in the directional pulling process of the pulling rod; (4) The first solidification stage: start the pulling device to pull the metal melt into the Ga-In-Sn liquid metal cooling medium of the cooling tank for directional solidification; the metal melt solidifies under the action of the first external magnetic field, and the magnetic field Mainly acts on the solid-liquid interface of the material; the first externally applied magnetic field can be a transverse steady magnetic field, a longitudinal steady magnetic field, a transverse traveling wave magnetic field, a longitudinal traveling wave magnetic field or a composite magnetic field formed by any two of the four magnetic fields; (5) The second solidification stage: when the material is immersed in the Ga-In-Sn liquid metal cooling medium at a set distance, the position of the magnetic field generator is adjusted so that the material solidifies under the action of the second external magnetic field; the second external magnetic field has the same characteristics as the first external magnetic field. Different types, strengths or frequencies of magnetic fields; (6) nth solidification stage; when the material is immersed in the Ga-In-Sn liquid metal cooling medium for a set distance, adjust the position of the magnetic field generator so that the material solidifies under the action of the nth external magnetic field; (7) After the metal material is cooled to room temperature, it is taken out, and the metal material has multiple solidified structures with different directional growth characteristics along the radial direction. 2. A device for preparing metal materials by multi-magnetic field-assisted directional solidification, characterized in that: applied to the method for preparing metal materials by multi-magnetic field-assisted directional solidification according to claim 1, comprising a smelting device, a magnetic field generating device, a vacuum chamber , cooling tank, temperature measurement system, pulling device, vacuuming system and experimental atmosphere source; The cooling tank is arranged at the bottom of the vacuum chamber, the smelting device is arranged in the vacuum chamber, the magnetic field generating device is arranged in the cooling tank, and the vacuum pumping system is connected to the vacuum chamber The inner cavity of the vacuum chamber is used for evacuating the vacuum chamber, and the experimental atmosphere source is connected to the inner cavity of the vacuum chamber, and is used to fill the experimental atmosphere into the vacuum chamber after being evacuated; The temperature system is used to monitor the temperature of the upper surface of the sample in the vacuum chamber; The smelting device includes an induction coil, a graphite sleeve and a crucible; the graphite sleeve is cylindrical graphite, the induction coil is wound on the outside of the graphite sleeve, the crucible is arranged in the graphite sleeve, and the crucible The bottom is connected with the pulling device, and the pulling device controls the crucible to move vertically in the graphite sleeve; the bottom of the graphite sleeve is provided with an annular graphite pad, and the bottom of the graphite pad is provided with a ceramic a pad, a graphite felt is arranged between the ceramic pad and the top plate of the cooling tank at the bottom; The magnetic field generating device includes a magnetic field generator, a thermal protective cover, a magnetic field control device and a power supply device; the magnetic field generator includes a longitudinal steady magnetic field generator, a transverse steady magnetic field generator, a longitudinal traveling wave magnetic field generator and a transverse traveling wave magnetic field generator. wave magnetic field generator; The longitudinal stable magnetic field generator is composed of a ring-shaped permanent magnet and a thermal protective sleeve sleeved on the outside of the ring-shaped permanent magnet, and can generate a stable and constant magnetic field parallel to the direction of directional solidification; The lateral stable magnetic field generator includes two square permanent magnets placed opposite to each other and a thermal protective sleeve sleeved on the outside of the square permanent magnets. Provide a transverse stable magnetic field; The longitudinal traveling wave magnetic field generator is composed of a longitudinally distributed copper coil and a thermal protective sleeve sleeved on the outside of the copper coil, and can generate a traveling wave magnetic field parallel to the direction of directional solidification; The transverse traveling wave magnetic field generator includes two rectangular coils placed opposite to each other and a thermal protective sleeve sleeved on the outside of the rectangular coils, which can generate a transverse traveling wave magnetic field; The magnetic field control device includes a magnetic field lifting component and a magnetic field translation component, wherein the magnetic field lifting component is composed of a lifting rod and a servo motor, and is used to control the lifting and lowering of the annular permanent magnet and the copper coil in the cooling tank cavity; The magnetic field translation assembly includes a translation support rod and a second servo motor, which are used to control the horizontal position of the square permanent magnet and the rectangular coil; The power supply device is used for supplying power to the internal coil of the magnetic field generating device. 3. The device for preparing metal materials by multi-magnetic field-assisted directional solidification according to claim 2, wherein the vacuum pumping system comprises a mechanical pump and a molecular pump, the mechanical pump is connected to the molecular pump, and the molecular pump is connected to the molecular pump. A pipeline is connected to the vacuum chamber. 4 . The device for preparing metal materials by multi-magnetic field assisted directional solidification according to claim 2 , wherein the induction coil is a red copper coil with circulating cooling water circulating inside. 5 . 5. The device for preparing metal materials by multi-magnetic field-assisted directional solidification according to claim 2, wherein the pulling device comprises a pulling motor and a pulling rod, and the bottom of the pulling rod is connected to the pulling motor, so The top of the pulling rod is connected to the crucible through a molybdenum alloy adapter, and the crucible is a cylindrical corundum crucible with a flat bottom. 6 . The device for preparing metal materials by multi-magnetic field assisted directional solidification according to claim 2 , wherein the thermal protective sleeve is an alumina ceramic sleeve. 7 . 7. The device for preparing metal materials by multi-magnetic field-assisted directional solidification according to claim 2, wherein the cooling tank comprises a cylindrical demagnetized stainless steel tank, a Ga-In-Sn liquid metal cooling medium and a circulating A copper tube for cooling water, the Ga-In-Sn liquid metal cooling medium is housed in the tank, and the copper tube is located in the Ga-In-Sn liquid metal cooling medium in the tank. 8 . The device for preparing metal materials by multi-magnetic field assisted directional solidification according to claim 2 , wherein the power supply device comprises an electrode flange and a power supply; the electrode flange is mounted on the side wall of the vacuum chamber. 9 . , the electrode flange is connected with the external power supply and the internal longitudinal traveling wave magnetic field generator and the transverse traveling wave magnetic field generator through wires. 9 . The device for preparing metal materials by multi-magnetic field assisted directional solidification according to claim 2 , wherein the side walls of the vacuum chamber and the cooling tank are double-layer water-cooling structures with a water-cooling interlayer inside, and the The water-cooled interlayer of the vacuum chamber and the cooling tank is connected to the water-cooler through pipes. 10 . The device for preparing metal materials by multi-magnetic field assisted directional solidification according to claim 2 , wherein the temperature measuring device is an infrared thermometer; and the infrared thermometer is installed on the top of the vacuum cavity. 11 .

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